Due to the worldwide increase in terrorist incidents, and the use of explosive devices in such incidents, there has been increased interest in building structures that are capable of withstanding very large applied forces (such as explosive blasts). Similarly, efforts have been made to retrofit existing structures with blast-resistant surfaces.
For example, some blast-resistant polymer coatings have been developed to “spray on” to existing masonry walls (such as concrete block and/or brick structures) in order to prevent the shattering of such structures in response to an explosive force. Such conventional blast-resistant coatings have proven effective for preventing the generation of potentially deadly debris by reducing the likelihood that such masonry structures shatter and/or decompose in response to the application of a blast force. While such conventional blast-resistant coatings are relatively easy to apply (via liquid spray, for example), they may fail to provide adequate blast resistance to preserve an existing structure during an excessive blast force (such as that accompanying the detonation of a relatively large explosive device).
Furthermore, such conventional blast-resistant coatings may not be effective for retrofitting some existing steel and/or cast iron structures for increased blast-resistance. For example, many existing structures, such as traffic structure systems and/or subterranean train structures are supported by relatively old cast iron structures having rusted, irregular surfaces and/or structural ribbing that may prevent an even coating of conventional “spray on” blast-resistant coatings. Furthermore, conventional blast-resistant polymer coatings may do little to further reinforce cast iron and/or poured concrete structures that may be subjected to very large blast forces originating inside the structure (for example, blast forces approaching and/or exceeding 50 kilopounds per square inch (ksi) that may be the result of large and/or powerful bombs that may be carried in luggage, in a vehicle, and/or pre-placed on an access pathway defined in a train structure).
In addition, it is well known that blast forces may be absorbed and/or mitigated using pumice powder and/or pebbles. For example, various military forces pack live ammunition in pumice. Because the pumice is air-filled and easily pulverized, it acts to absorb the explosive blast and/or shock should a single round of ammunition be ignited. This blast and/or shock absorption quality may prevent the chain-reaction explosion of some or all of the remaining rounds packed with the ignited round. While pumice has been shown to be an excellent blast and/or shock absorbing material, it is not easily integrated into a modular reinforcement structure, as it is most effective as a pulverizable pebble. Furthermore, pumice (or perlite materials, which have similar pulverizable characteristics) on its own, cannot prevent the penetration of shrapnel or other projectiles that may accompany the explosion of a bomb.
Thus, there exists a need in the art for a modular panel and/or reinforcing structure that is capable of absorbing and/or redirecting large blast forces (at or near 50 ksi, for example) that may be exerted on existing structures or structural components. There further exists a need in the art for such a modular panel and/or reinforcing structure that combines excellent shock absorption characteristics with other characteristics (such as, for example anti-ballistic capabilities, shrapnel protection, and/or blast-deflection capabilities) that may better protect a potentially vulnerable structure.